Patients with slow-transit constipation may have either normal or delayed proximal colonic emptying which cannot be easily detected by radioopaque markers or 'spot' scintigraphic images at 4 and 24 hours. In this pilot study, our aim was to measure the rate of proximal colonic emptying using a modified scintigraphic transit study. Methods: 7 healthy volunteers with no symptoms of functional bowel disease by Rome Criteria ingested a methacrylate-coated delayed-release capsule containing 111In adsorbed on activated charcoal particles at 12 midnight. From 7 a.m. to 4 p.m. on 2 consecutive days (i.e. hours 7 to 16 and 32 to 40 after capsule ingestion), anterior and posterior scans were taken with a gamma camera. Regions of interest (ROI) were drawn over the ascending, transverse, descending and rectosigmoid colon, with decay and depth correction. Volunteers received a standardized breakfast (550 Kcal) and lunch (422Kcal) on these 2 days.